Jscrollpane in matlab - swing

Question

I am trying to use some java gui in my matlab code.
I want to create a Jpanel containing lots of buttons , and add this Jpanel to a JscrollPane to be able to scroll up and down, right and left through the Jpanel.
I tried using JavaComponent() function as described in : http://undocumentedmatlab.com/blog/javacomponent
here is my code:
[jpanel1, hpanel1] = javacomponent('javax.swing.JPanel');
[jButton1, hButton1] = javacomponent('javax.swing.JButton');
[jscroll, hscroll] = javacomponent('javax.swing.JScrollPane');
jButton1.setText('Click again!');
set(hButton1,'position',[5 5 50 50])
set(hpanel1,'position',[50 50 500 500],'BackgroundColor','white');
jpanel1.add(jButton1);
jscroll.add(jpanel1);
The panel and button are created but I can't find the scrollpane, tried setting the jscroll to visible with no results.
WHat am I missing out??

Answer 1

You only need to use javacomponent once, to display the outer-most java container, i.e. JScrollPane in your case. Just assemble your components inside JPanel container and then pass that to JScrollPane constructor.
Note that it is safer to create your objects with javaObjectEDT so that subsequent method calls run on EDT - otherwise you could face a deadlock / race condition.
Finally, note how you can use getpixelposition and 'normalized' units for the container created by javacomponent to make your JScrollPane fill the entire parent drawing area, and behave better on resizing.
jButton1 = javaObjectEDT('javax.swing.JButton', 'Button 1');
jButton2 = javaObjectEDT('javax.swing.JButton', 'Button 2');
jPanel = javax.swing.JPanel();
jPanel.add(jButton1);
jPanel.add(jButton2);
jScrollPane = javax.swing.JScrollPane(jPanel);
hFig = figure();
hParent = uicontainer('Parent',hFig);
parentPixelPos = getpixelposition(hParent);
pos = [1,1,parentPixelPos(3),parentPixelPos(4)]; % fill the parent uicontainer completely
[~, hContainer] = javacomponent(jScrollPane, pos, hParent);
set(hContainer, 'Units', 'normalized'); % better behavior on resizing

Answer 2

jscroll.add(jpanel1);
You should never add components to a scroll pane. A JScrollPane has its own custom layout manager to display the scrollbars and the viewport.
So instead you need to add the panel to the viewport:
jscroll.setViewportView( jpanel1 );
However, this may still not work as the following code looks like it is trying to set the size/location of the component which implies a null layout is being used:
set(hButton1,'position',[5 5 50 50])
Normally it is the responsibility of the layout manager to determine the size/location of a component and the scrollbars of the scrollpane will only be displayed is the preferred size of the panel is greater than the size of the scrollpane.
I don't know that the benefit of using MatLab is. I suggest you just use normal Swing. See examples from the Swing tutorial on Using Layout Managers.